Fault Diagnosis For Power Electronic Circuits Based On Hybrid System Model

With the emerging of the new high-performance devices, power electronic technology has developed rapidly. It has been widely used in the domestic electrical, aviation and aerospace, power systems and industrial fields. Power electronic devices are usually used as power supply in these areas and they must have very high safety and reliability, so the fault diagnosis of power electronic equipment problems have received attention gradually.In the operation course of the power electronic circuits, the on/off status of the power switching device enable the circuit to show the discrete mode switching characteristics and state variables continuous feature, so the power electronic circuits can be described as hybrid systems. The structural and parametric fault diagnosis of the circutis can be discussed by taking the perspective of hybrid systems.Firstly, this article introduces the significance, purpose and the current research of the fault diagnosis, and analyzes the advantages and disadvantages of the various fault diagnosis methods.By comparing the fault diagnosis methods, the models-based diagnosis method for power electronic circuit fault diagnosis is selected.Based on the hybrid system theory and the basic laws of the circuits, this article derives the hybrid automaton models of the Boost circuit and other circuits, then use the hybrid automaton diagrams describe the hybrid characteristics of the circuits. Based on the hybrid models, the structural fault diagnosis method is discussed combining with the event identification method, and the parametric fault diagnosis method is discussed with the help of least square indetification algorithm. Then their applications in the Buck and Boost circuits are analyzed in detail. Finally, the effec-tiveness of the parametric fault diagnosis method of the circuit is verified by simulation,and the effectiveness of the structural fault diagnosis method of the circuit is verified by experiment.